Accumulated Other Comprehensive Income (Loss) - Components of Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income [Roll Forward]
Other comprehensive income (loss) before reclassifications	$ 33	$ (23)	$ (4)
Amounts reclassified from AOCI	(9)	16	9
Tax benefit (expense)	(7)	0	(2)
Other comprehensive income (loss)	17	(7)	3
Unrealized gain (loss) on sales hedging
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(9)	6	(1)
Other comprehensive income (loss) before reclassifications	38	(26)	1
Amounts reclassified from AOCI	(13)	8	7
Tax benefit (expense)	(4)	3	(1)
Other comprehensive income (loss)	21	(15)	7
Ending balance	12	(9)	6
Unrealized (loss) gain on forward interest rate swaps
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(9)	(15)	(15)
Other comprehensive income (loss) before reclassifications	8	1	(1)
Amounts reclassified from AOCI	4	8	2
Tax benefit (expense)	(3)	(3)	(1)
Other comprehensive income (loss)	9	6	0
Ending balance	0	(9)	(15)
Foreign Currency translation adjustments
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(34)	(36)	(32)
Other comprehensive income (loss) before reclassifications	(13)	2	(4)
Amounts reclassified from AOCI	0	0	0
Tax benefit (expense)	0	0	0
Other comprehensive income (loss)	(13)	2	(4)
Ending balance	(47)	(34)	(36)
Total
Accumulated Other Comprehensive Income [Roll Forward]
Beginning balance	(52)	(45)	(48)
Ending balance	$ (35)	$ (52)	$ (45)